Characterization of CNG induced transition regimes of reactivity-controlled-combustion of Madhuca longifolia biodiesel: An experimental case study

This study demonstrated the synergistic capability of split-injection techniques to achieve the better emission-performance-stability endeavor of a diesel engine operating under CNG-biodiesel reactivity-controlled compression ignition (RCCI) mode. CNG will enhance a diesel engine's performances characteristics and reduce emissions when combined with a split injection technique. The biodiesel yielded from Mahua oil was characterized by Gas Chromatography-Mass spectrometry (GC-MS) analysis and classified biodiesel components. However, various physical properties were determined from GC-MS analytical responses. A systematic split-injection effort was tested for each pilot, and the main injection at different angles fueled with CNG-biodiesel to achieve the RCCI mode of combustion. The variance coefficient for indicated mean effective pressure (COVIMEP) data demonstrated more reliable engine operation when fueling with CNG-biodiesel instead of fossil diesel. The analysis showed the highest exergy efficiency (30%) and the lowest brake specific energy consumption (8.64%) as performances characteristics, reported for RCCI mode of operation. This experimental study showed the lowest value of NOx, Soot, and UHC emissions under RCCI regimes. These values of NOx, Soot, and UHC emissions are 21.4%, 33.4%, 50% higher than plain biodiesel operation and 75.28%, 21.29%, and 83.87% better than plain fossil diesel operation. Therefore, the analysis showed the synergistic advantages of a CNG-biodiesel RCCI engine operating with the split injection mode to achieve higher efficiency and lower emission characteristics.